Age at diagnosis:11 month-old female infant. According to the parents, trauma of the right shoulder. Presumed luxation or rupture.

Pathomorphology or Pathophysiology of this disease :

Malignant tumor of the synovial lining, i.e. histologically, the tumor imitates synovial tissue.Origin is from the joint's capsule, synovial sheath and bursae. The synovial sarcoma originates more frequently from the synovial sheath as from the capsule.The tumor's borders are usually sharp, without proof of peritumoral edema.Calcifications are found in 30% of the cases, often septation and fluid levels due to hemorrhaging. Thereby somewhat inhomogenic tumor structure.

Radiological findings:

MRI 1: T2-transversal: Signal intense mass of about 6 x 6 x 5cm in the right axilla with expansion up into the subscapular soft tissue. Laterally, the transversally sliced humerus can be seen.

MRI 2: T1-SE cor: Mass in the right axilla with expansion up into the subscapular soft tissue. Practically isointense with muscle, solitary signal absence in both weighted images.

MRI 3: Proton weighted image with fat saturation; coronal. The tumor lies on the proximal humerus, the scapula and the thoracic wall. One infiltration of the bony structures is not seen.

MRI 4: T1-SE-semi-sag after contrast: diffuse uptake of contrast.

MRI 5: T1-SE-semi-sag without contrast.

Diagnosis confirmation:

Surgery / Histo

Which DD would be also possible with the radiological findings:

A diagnosis with imaging alone is not always possible. Principally, many other soft tissue tumors are possible. In some instances, a pigmented, villonodular synovialitis (PVNS) could be discussed.

Course / Prognosis / Frequency / Other :

In this case, an adjuvant radiochemotherapy was performed after tumor resection (histological findings: R1-resection). About 1.5 years after the begin of symptoms, there have been no posttherapeutic changes confirmed by imaging.

Comments of the author about the case:

A patient with the same diagnosis was introduced to Ms. Hahn (Dresden). In our example, the tumor was somewhat more homogenically structured. The course under treatment seems similar so far .